Semi-solid state means that there is both liquid and solid state in the metal raw material. After continuous stirring, the alloy has low apparent viscosity and is easy to deform. It can fill the mold cavity with very little force. Semi-solid die-casting is to use a die-casting machine to melt semi-solid metal into a certain shape of metal mold to form precision die-casting parts. Its essential characteristics are high pressure and high speed. Semi-solid die casting includes rheological die casting and thixotropic die casting. Rheological die-casting is to directly inject semi-solid blanks into the cavity to form a part, and thixotropic die-casting is to pre-form semi-solid slurry into ingots of a certain size, reheat to semi-solid temperature if necessary, and Send to the pressure chamber for die casting.
Compared with the traditional die-casting technology, the semi-solid die-casting technology can reduce the content of pores in the die-casting parts, making the die-casting parts more compact, not only improving the thermal conductivity of the die-casting parts, but also making the chassis smaller and lighter Widely used, including base station heat sink, heat dissipation shell, mobile phone shell and fan blade, etc. Research shows that for chips with the same power consumption, semi-solid die castings are used, and the temperature of the chip chassis can be reduced by more than 7 ° C compared with traditional die castings. The inflation plate is used on the heat dissipation tooth plate, that is, the aluminum plate of a certain specification is chemically surface-treated, and the evaporator piping diagram is printed on the mating surface of the aluminum plate. After rolling and annealing, it is inflated with nitrogen, the aluminum plate pipe is swollen on one side, and then the aluminum plate is sheared and punched. Inflatable panels have the characteristics of high heat conduction efficiency, fast cooling speed and beautiful appearance. The traditional usage scenarios include refrigerators, freezers, water dispensers with refrigeration function, display cabinets, wine cabinets and IT equipment with special heat dissipation requirements. The heat sink, which combines the semi-solid die-casting process and the inflation board technology, is expected to become a mainstream application in 5G base stations.
The pattern of die casting suppliers is stable
Die-casting machine is the upstream core equipment of die-casting parts. According to different downstream applications, it can be divided into two types: large and medium-sized. Large-scale equipment is mainly used in automobiles and communications, and small- and medium-sized equipment is mainly used in 3C. At present, my country's die-casting machine market is fully competitive, and domestic manufacturers have formed a three-legged pattern of Lijin, Yizumi and Haitian. Foreign import suppliers are mainly Buhler, Indra, Fulai and Yite.
Participants in my country's communications industry die castings mainly include ZHRX Precision Die Casting Technology Company (SZFR acquired 51% equity of ZHRX in 2018), SZYB Semi-Solid Die Casting Technology Group, SZTR Precision Machinery, SZCX Precision, SZDS Precision and AHDF Technology. ZHRX Precision Die Casting Technology Company and SZYB Semi-Solid Die Casting Technology Group lead the number of patents in semi-solid die castings.